


Pretty Princess

by orphan_account



Category: Supernatural
Genre: Alpha Dean, Barebacking, Bottom Sam, Dresses, Feminization, Implied Mpreg, Knotting, M/M, Mating Cycles/In Heat, Omega Sam, Sam is Sixteen Years Old, Smut, Top Dean, Underage Sex
Language: English
Status: Completed
Published: 2017-10-15
Updated: 2017-10-15
Packaged: 2019-01-17 14:45:39
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 1,947
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12367992
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: Sam is excited to go to a Halloween Party… And then his first heat hits.





	Pretty Princess

**Author's Note:**

> Written for Kinktober and Inktober Day 14 (incest and Disney).  
> Also written for SPN ABO Bingo Square: heat/rut  
> As of now there are no plans to continue any Kinktober ficlets, they are meant to be just quick little reads for you guys.

Sam took a deep breath, straightening the bright yellow dress over his hips. The cheap fabric crinkled a little against his chest, and his lower back itched where a stray seam tickled, but it didn’t matter. He was sixteen now, and Dean _finally_ okayed him going to a party.

Sam had been asked to the local school Halloween party by one of the Alpha seniors he’d been crushing on since they arrived in this town a month ago. Maybe, Sam figured, tonight he could just be a normal guy. 

 

He took one more look in the mirror, fixing the nude lipstick on his pouty lips and did a little spin. Save for his not quite long enough hair, the Belle ball gown fit his slender omega form perfectly. He ran his fingers over the swell of the dress, his stomach twisting in all sorts of nervous knots. 

He sat on the edge of the tub, slipping on the heels that matched the dress. His stomach knotted further. Sam grimaced, setting a hand on his lower belly. A clammy sweat broke out on his forehead, nausea peaking. 

Sam stood, trying to get to the toilet before he lost his small dinner. As soon as he was vertical, the muscles in his stomach released, pressure and discomfort stopping completely. Sam breathed a sigh of relief. No fucking way was he going to be sick during _this_ night.

He took a couple of tentative steps toward the sink when his stomach clenched again, hard enough that Sam gave a cry of surprise and pain. A hot gush of slick dribbled out of his ass, a warm burn replacing the pain. 

Realization struck then, and Sam’s eyes filled with involuntary tears. Not tonight. Of all the possible nights for him to have his first heat, it _had_ to be tonight? 

A sob of frustration bubbled out of Sam and he slid down onto the floor. He was already feeling the effects, his growing need for an Alpha’s knot, the increased arousal, everything. Sliding onto the floor and curling around himself, Sam squeezed his legs together, willing the pressure to ease up. 

 

Nearly ten minutes later, Sam heard the door of the motel open. Dean’s scent smacked him like a freight train, strong and firm and _Alpha_. Another dribble of slick ran down Sam’s ass. He could hear the shuffle of Dean’s boots, the clink of his keys being set down. 

“Sammy?” Dean’s voice was on the edge of panic.

“Leave me alone,” Sam huffed. He wanted to stay silent, ride out his first heat in a shameful puddle on the bathroom floor - but this was Dean.

“Sammy, let me in!” Dean cried, his voice near the door now. The handle jiggled. “Sam!”

“Go away!” Sam cried again, his voice breaking into a weak moan when his stomach fluttered. 

“Sam, please you can’t handle this on your own.” 

“Yes I can!”

“You could die, Sam! Let me in or I’m fucking knocking the door down.”

Sam sat up slowly. Despite the pain in his stomach, he knew their father would kill him if Dean caused that much damage to the room. He unlocked the door before settling back onto the floor, close to tears.

Dean slammed the door open, stopping short when he saw Sam. In his aroused haze, Sam had forgotten his costume, and that Dean hadn’t seen it. 

“Sammy—“ 

Sam’s head whipped up. Dean’s voice was broken, thick with fury - or lust. His body was relaxed, hands open, pupils dilated. Lust. Sam curled tighter against himself.

“I’m scared.”

Those simple words broke whatever spell Dean had been under. He shot into action, crouching and scooping Sam up like a bride on her wedding night. Sam didn’t bother to argue, just buried his face in Dean’s neck and inhaled. 

“I got you, Sammy. Look so pretty, princess. Woulda been the hit of the party,” Dean cooed, laying Sam on his bed. He walked away, and Sam sobbed brokenly.

“Just getting a cloth, Sammy. Just breathe,” Dean called from the bathroom, turning the water on. 

He returned seconds later as promised, and began wiping Sam’s face with the cool cloth. Sam looked up at him, his eyes focusing slowly. His hero. His big brother.

“Dean—“

“I’m here, Sammy.”

“No— Be—“ Sam’s throat closed, too scared to speak the words aloud. He grabbed Dean’s hand, pulling the cloth away and pressing a kiss to his fingers. Heart pounding in his chest, Sam slid Dean’s hand down, under the mass of fabric, to where his cock rested, hard and bare.

“Sam, we can’t—“

“Why not?”

“I’m your brother.”

“Brothers mate all the time, Dean. Please.”

Dean swallowed hard. Sam could still see resistance in his eyes, but his hand curled loosely around his cock.

“You weren’t gonna wear underwear to the party?” Dean whispered, stroking Sam lazily under the dress.

“No. The— My date, I—“ Sam looked down, ashamed. 

The snarl that slipped from Dean’s mouth made Sam cower into the bed. He yanked his hand away.

“You were gonna let him fuck you?”

“Dean—

“You’re better than that, Sam! What were you thinking?” Dean snapped.

“Don’t, please. You sleep around, I just wanted to feel normal.” Sam knew he sounded whiny, but couldn’t bring himself to care. He was in pain and Dean’s scent was making him ache in the worst way. 

“You’re better than me, Sam! You deserve more than someone like me.”

“I’m looking for exactly someone like you!” Sam snapped before he’d thought it through. Their eyes both widened, mirroring one another. 

“Sam—“

“Go away,” Sam whispered, shame overpowering every other emotion he had. 

“Sam, no—“

“Go!” Sam climbed off the bed, trying - and failing - to hurry back to the bathroom. The dress made it almost impossible to run, however, and Dean tackled him down, their bodies rolling across the floor as they fought for the upper hand. 

Dean won - Dean always won - and pinned Sam under him. Sam’s cock throbbed, feeling Dean’s heat even under the layers of dress and denim. 

“Just listen to me, Sammy,” Dean said, his voice desperate. Sam scowled, about to respond when Dean lowered his head, covering Sam’s lips with his own. 

The kiss was desperate, teeth clashing as they tasted the forbidden mouth they’d silently loved for for years. Dean’s hands found their way between them, pushing under the fabric. When one reached his cock, he gave almost a painful squeeze, making Sam shout into his mouth.

Dean pulled back, the light smattering of scruff on his chin tickling Sam’s cheek as he pressed wet kisses along it. He nipped Sam’s earlobe. 

“My princess.”

Sam whimpered, grabbing Dean’s hips. He bucked up against Dean’s leg, the crinkle of the cheap fabric now sounding positively pornographic. 

Dean got off Sam and yanked him upright, shoving him onto the bed. He shoved the dress up, baring his ass to the cool air of the room.

“Dean, please—“ Sam panted, his hands scrabbling across the mattress.

“Please what?” Dean ran his thumb over Sam’s wet hole, making a small noise of approval when it resulted in more slick dribbling out.

“It hurts, Dean— I need it.”

Dean laid over Sam’s thin body, his denim clad cock rubbing against his ass as he kissed over Sam’s bare neck. “I got you, Princess. You just make some pretty noises for big brother, okay?”

Sam flushed, burying his face in the mattress. Dean’s comforting weight disappeared for a moment. 

He nearly jumped off the bed when Dean’s tongue slipped in between the globes of his ass. Dean grabbed his hips in a bruising grip, keeping him pinned to the bed as he drove his tongue into Sam’s hole.

Torture was the only way Sam could describe what Dean was doing. Tongue, fingers, nips of teeth and gentle, teasing kisses, Sam felt completely taken apart. Dean had him on the edge of orgasm for nearly thirty minutes, and no amount of begging or screaming would rush him along. When he finally stood and Sam heard the sound of the zipper, his heart stopped for a moment. This was it. What he’d been waiting for - wishing for - for years. 

Dean’s body covered his once more, his hand grabbing Sam’s and twining their fingers. Sam could feel the line of his bare cock nestled in the crack of his ass, sliding slick and smooth. 

“Ready for this, Sammy?”

“Yes— I need it, I—“

“Shh,” Dean kissed the shell of his ear. “Don’t beg. Just moan for me, Princess.” 

Dean pressed in as soon as he finished speaking, and Sam didn’t bother trying to stifle his noise.

The thick stretch of Dean’s cock burned in the best of ways, stretching Sam wide and making him curl his toes against the ratty fabric. 

When Dean bottomed out and Sam felt the tickle of his hair and the hot press of their balls, he couldn’t hold back the orgasm that pushed forward. He clamped down on Dean’s cock, screaming Dean’s name until his voice broke. 

Dean picked up a brutal pace, murmuring quiet praises in his ear: how nice he felt, how pretty he looked in the dress and makeup, to just let go, come on his cock, enjoy this, scream for him. 

Sam lost track of time. All he could focus on was Dean’s body, the way they fit perfectly together. Even his orgasms were gentler, two, three, come poured from his cock in weak streams, his moans fading into quiet sighs as his rim fluttered around Dean’s swelling knot.

 

“Gonna wreck your dress when I come, princess. Cover you.”

Sam’s eyes snapped open. He looked back as well as he could. “Please, no— knot me, Dean.”

“Sammy, I don’t have a condom,” Dean panted. “I could knock you up, you’re in heat.”

Sam stared at the ratty bedspread, letting his hand snake down to touch his flat stomach, still covered in the cheap fabric. 

“Will— Will I still be your pretty princess if I’m carrying your litter?” He asked in a voice much smaller than his sixteen years.

Dean’s hips stuttered. He nuzzled Sam’s ear. “You will _always_ be my pretty princess, Sammy. You’re big brother’s baby.”

Sam smiled a little. He pushed his ass out a little father. “Then. I’m ready, Dean. I’m ready for big brother to give me babies.”

Dean snarled, his speed increasing. His knot swelled quickly, Sam’s words urging him on. Sam screamed against the mattress, slick squelching out around Dean’s cock as his ass was pounded. Dean’s teeth sank into Sam’s shoulder as his knot finally caught, tying them together. 

The first spurt of come filling him had Sam coming hard again, his body writhing under Dean helplessly. Dean held tight, forcing them entirely on the bed. He laid over Sam, pinning him down as his body shook with the main brunt of his orgasm. As it faded, he loosened his grip on Sam’s bruised hips, rolling them to their sides.

Sam reached back, his hand shaking as he felt where they were tied.

“I’m gonna get pregnant—“

“I’m sorry, Sammy—I”

“Don’t.” Sam looked over his shoulder. “I’m sixteen. But I’m smart. And so are you. I wanted this - I’m ready for this. I’m scared, but— We can handle this, Dean— if this is the mating that knocks me up—“

“Yeah, Sammy I know. I’m just..” he shook his head. “I’m glad it’s you. But dad—“

“Has to understand. He had to see this coming.”

Dean swallowed hard. He let his arm hang over Sam’s waist, absentmindedly dancing over his stomach. Sam grabbed it, twining their fingers. “We’ll figure it out.”

“We always do,” Dean agreed.

 


End file.
